Gun breech



April 5, 1938. i J. HASEK GUN BREEGH Filed March 8, 1935 Jar-osJ av Hi58K INVENT E ai AfT v.

Patented Apr. 5, 1938 UNITED STATES PATENT OFFICE GUN BREECH ApplicationMarch 8, 1935, Serial No. 9,946 In Czechoslovakia March 8, 1934 1 Claim.

This invention relates to a gun-breech in which a system of screwthreaded parts is employed, that is to say a nut and a spindle which,when the breech is closed, occupies a position in which its geometricalaxis coincides with the geometrical axis of the bore of the gun barrel.This position will hereinafter be referred to as the axial position. Inorder to complete the closure of the breech in the axial position thethreaded spindle is screwed out of the nut until an axial pressure isdeveloped which is suiiicient to effect the tight closure of the gun.

To open the breech, the spindle is first screwed into the nut, and thenthis system of screw threaded parts is shifted into a position whichcompletely discloses the breech aperture, that is to say in which thebreech is fully opened for re-loading. The intrusion of the spindle intothe nut on opening, and the withdrawal of the spindle from the nut onclosing the breech is effected by a rotary movement of one of the twoelements of the screw threaded system of parts when in the axialposition. Thus, either the nut rotates while the spindle is lockedagainst rotation and merely moves axially, or the spindle rotates in afixed nut in which case the spindle is axially displaced simultaneouslywith its rotation.

The shifting of the screw breech could be effected either by rectilineardisplacement or by rectilinear rolling movement. In accordance with thepresent invention, however, the shifting of the breech system from theloading position to the axial position is effected on an arcuate pathwith the aid of members which are positively controlled by guidingmeans.

Forms of construction embodying the invention are shown by way ofexample and in diagrammatic form in the accompanying drawing, in which:

Fig. 1 is a longitudinal section of one form of construction of thebreech according to the invention.

Fig. 2 is a section taken on the line II-II of Fig. 1.

Fig. 3 shows the breech screw alone, in elevation, as seen from theforward end, that is to say from the top in Fig. 1.

Fig. 4 shows, in longitudinal section, a modified form of constructionof the invention which is of very special significance.

Fig. 5 is a substantially longitudinal sectional View of the couplingelements of a closure device according to Fig. 1, the view beingillustrated on an enlarged scale, and

Fig. 6 is a substantially longitudinal sectional view of the couplingelements of a closure device according to Fig. 4, the view beingillustrated on an enlarged scale.

Referring to Fig. 1, the breech nut I0, together with the screw spindleII, is held in a spring 6 holder or rim I2 which is carried by the lowerpart (as viewed in Figure 1) of a hub I2 of square cross-section fittingover the squared upper portion I3 of a rocking shaft I5. Extending fromthe upper part of the hub I2 is a band I4 10 of polygonal shape whichengages over the inner end of the spindle II, said inner end beingsimilarly shaped. This looks the spindle II against rotation and, as aresult, when the breech nut I0 is rotated, the spindle II moves onlyaxially.

In order to prevent unintentional rotation of the nut ID, the holder I2is resilient, preferably in the form of opposed spring arms, as shownmost clearly in Figure 2, whereby there is always an adequate frictionalresistance between'these 20 arms and the nut I I].

The shaft I5 is rotatably mounted in thebody I6 of the gun barrel, andcarries at its outer end a lever Il terminating in a projecting pin I8,which may be in the form of a roller, or the like. In the body of thegun barrel I6 there is axially mounted a cam plate I9 which is providedwith a crank-handle 20. This plate I9 merges in the middle with a hollowscrew spindle which is screwed into a threaded socket 2| formed in thebody I6 of the gun-barrel. Loading is effected through the middle ofthis screw spindle. When the crank-handle 20 is operated in the onedirection of rotation, the cam plate I9 is retracted bodily, andconversely, is intruded when the bandle is turned in the oppositedirection. In the plate I9 there is provided a groove 22 (see Fig. 3)engaged by the end I8 of the above-mentioned lever I1. This groove isprovided with a cam portion, whereby at a certain point in the rotationof the plate I9, the rocking member I3 is pivotally moved through anangle a which is required to swing the breech assembly from the axialposition into the open position for loading. During the time that thebreech spindle I I moves axially in the nut I0, a concentric portion ofthe above-mentioned groove is in engagement with the pin or roller I8,and, therefore, no pivotal movement of the rocking member I3 takesplace. The pin or roller I8 is, however, ultimately forced to one sideby the cam portion of the groove 22, and this swings the breechassembly, including nut I0 and spindle II, bodily into the dot-anddashposition of Figure 2. During this swinging, 55

the breech assembly is yieldably supported in the direction of closureby a spring 23 (see Fig. 2) secured to the body of the gun barrel. Thisspring is preferably so dimensioned that it is capable ofcounterbalancing the weight of the breech assembly when the breechaction involves vertical movement of this assembly. The course andvelocity of the breech-opening motion can be varied within wide limitsby varying the shape of the cam groove 22.

The breech nut I0 is provided with teeth 24 adapted tobe engaged bycorresponding teeth 24' on the hollow screw spindle extension 27 of theplate l9 when the breech is closed. (see Figs. 1 and 5). Thisarrangement constitutes a dog clutch for a temporarily restricteddriving of the breech nut, the mode of operation being as follows: Whenthe breech is closed the said clutch 24, 24 is in full engagement. Onopening, that is to say when the plate I9 is rotated, the dog clutchfirst causes the breech nut I 0 to be rotated along with the plate IS,with the result that the spindle H becomes axially displaced rear-Wardly In this nut, and the tight closure of the gun barrel is thusrelieved. Since, however, the breech nut It does not move axially whileon the other hand the plate l9 does move back during rotation, a pointis reached when the dog clutch 24, 24 comes out of engagement. From thismoment on, for the rest of the opening action, the breech nut I0 is heldfast against rota tion by the frictional resistance between this nutand. the holder sleeve I2. At the same moment the projecting pin N3 ofthe lever l1 engages the cam portion of the guide groove 22, with theresult that the rocking shaft [5 and the hub [2' are bodily pivoted,thereby swinging the breech assembly from the axial position into aposition in which the loading aperture is fully disclosed, that is tosay in which the breech is opened.

In closing the breech, the reverse procedure takes place, the crucialpoint being that at which the dog clutch 2 1' is re-engaged. Since thereis no extrinsic reason for rotation of the breech nut H], which is heldfast by friction, the teeth 24, 24' of the dog clutch returnautomatically into the same relative positions which they occupied atthe moment of disengagement.

A modified form of construction of the invention is shown in Figs. 4 and6. The threading rocking member I 3 which projects through a hub ofsquare cross-section, said hub being integral with the breech block 26.The supporting spindle 21 effects the pressing of the breechblock 26into the position of closure. The breechblock consists of a sufiicientlyruggedly dimensioned disc which closes the end of the barrel 16 in theaxial position, through being pressed up by the hollow supportingspindle 27.

In opening, the disc 26 is slackened back by virtue of the fact that thesupporting spindle travels back and takes the disc with it by means ofan overhanging rim 25 of semicircular shape engaging with an annularflange 26' on the breech block 26. The rocking member I3 is connectedwith the lever I l which is provided with a pin I8 engaging in the camgroove 22 of the cam plate. These parts are so proportioned and the camgroove 22 is so arranged that as soon as the breech-block 26 has beensufiiciently retracted in the breech-opening operation, the pin I 8 ofthe lever II on the outer end of the rocking member I3 comes intoengagement with the cam portion of the control groove 22, whereupon therocking member I3 is pivoted and swings the breech-block 26 into theopen position.

I claim:

In a gun, a breech block, a rotatable cam plate mounted coaxially withthe gun barrel, and means operable upon rotation of said plate forautomatically effecting, in succession, an axial movement of the breechblock and an arouate lateral bodily movement thereof, said plate havinga cam groove therein, and said means including a rocking membereccentrically journaled in the gun barrel, means connecting said rockingmember with said breech block, and a crank pin on said rocking memberserving as a cam follower and riding in said cam groove.

JAROSLAV HAsEK.

